Chromium-induced genotoxicity in plants: mechanisms and sustainable remediation approaches

Chromium is a widespread environmental contaminant, with its hexavalent form [Cr(VI)] recognized as highly toxic due to its solubility, mobility, and bioavailability. Cr absorption and intracellular redox reactions in plant systems generate free radicals that interfere with vital phytochemical processes. Oxidative stress, driven by excessive reactive oxygen species (ROS) production, causes DNA damage, chromosomal abnormalities, impaired seed germination, stunted seedling growth, disruption of photosynthesis and nutrient uptake. Genotoxic and mutagenic impacts include chromosomal aberrations, micronuclei formation, and epigenetic alterations. Plants counteract these effects through antioxidative defense systems that involve both non-enzymatic and enzymatic antioxidants. Microorganisms also contribute to detoxification by biosorption, bioaccumulation, redox transformations, and secretion of extracellular polymeric substances. It facilitates the toxicity reduction of Cr by converting Cr(VI) to Cr(III). An integrated remediation strategy involving plant antioxidative defenses and microbial interactions offers a sustainable approach for the restoration of Cr-contaminated ecosystems. This review is a synthetic conceptualization of current knowledge on the molecular and genotoxic impacts of Cr in plants, highlighting plant-microbe interactions, ROS-mediated responses, and eco-friendly remediation strategies. It emphasizes the need for advancing phytoremediation and microbial biotechnology, along with emerging genomic and omics-based approaches, to mitigate Cr-induced stress and safeguard agricultural productivity and ecosystem health.